This invention relates to a camera provided with a barrier for protecting a barrel in its retraction position.
In general, a camera provided with a barrier needs to have a means for opening and closing the barrier. This makes the size of the entire camera larger. Particularly, in the case of use of a barrier for covering the entire barrel which houses the lens, not a lens barrier for covering a lens, the barrier itself is large and a device for driving the barrier tends to be large. Thus, how the size of the entire camera can be made smaller is an important object to attain.
FIG. 16 shows an exemplary barrier driving mechanism of prior art. A gear 201 is mounted at the rear end of an illustrated barrel 200, and a motor 202 for driving the barrel 200 is provided near the barrel 200. A gear 203 is secured on an output shaft of the motor 202, and is in mesh with the gear 201. A cam groove 204 is formed in the side wall of the barrel 200. An unillustrated pin is fitted into the cam groove 204 sideways. As the barrel 200 is drivingly rotated by the motor 202, it moves between an unillustrated retracted position and a projection position located more forward than the retraction position.
A barrier 205 is provided before the barrel 200 in its retraction position. The barrier 205 is rotatable about a rotatable shaft 206 extending in the forward/backward direction. The barrier 205 rotates between a closure position (shown) where it covers the front end of the barrel 200 and an open position away from the closure position. A claw member 208 is mounted at the rear end of the rotatable shaft 206, and a coil spring 207 is mounted over the rotatable shaft 206 and the claw member 208. The barrier 205 is held in its closure position by an elastic force of the coil spring 207.
A rotatable member 209 is provided between the barrier 205 and the barrel 200, rotatably about a rotatable shaft 210 extending in the vertical direction. A pin 209a which comes into contact with the front end of the barrel 200 projects at the rear end of the rotatable member 209. The rotatable member 209 is biased by a spring 211 in such a direction as to hold a front end 209b of the rotatable member 209 in contact with the claw member 208.
In this construction, when the barrel 200 in its retraction position is rotated by operating the motor 202, the barrel 200 moves forward (indicated by the arrow A) by interaction of the cam groove 204 and the unillustrated pin, and a front end surface 200a of the barrel 200 presses the pin 209a forward. Thereby, the rotatable member 209 rotates in a direction indicated by the arrow B, and its front end 209b rotates the claw member 208 and the barrier 205 against the elastic force of the coil spring 207 in a direction indicated by the arrow C from the closure position.
In this construction, the motor 202 is used also as a driving source of the barrier 205 so as to make the construction smaller.
In the above construction, when the barrel 200 is moved forward, it has to press the pin 209b forward against the elastic force of the coil spring 207. In other words, the driving force of the motor 202 needs to be sufficient to move the barrel 200 forward and to rotate the claw member 208 and the barrier 205 against the elastic force of the coil spring 207. This requires the motor 202 to have a large capacity, thereby standing as a hindrance to making the size of the entire construction smaller and fabricating it at a reduced cost.